Experimental investigations on the fatigue behavior of a near-alpha titanium alloy under typical cyclic loadings were carried out to simulate the service loading states applied on the engine blades.The axial stress-co...Experimental investigations on the fatigue behavior of a near-alpha titanium alloy under typical cyclic loadings were carried out to simulate the service loading states applied on the engine blades.The axial stress-controlled tension–tension low-cycle fatigue（LCF） tests were carried out over a range of maximum stresses and stress ratios.The rotary bending tests were conducted using a step-loading procedure to reveal the high-cycle fatigue（HCF） limit stresses.The cyclic softening effect is observed in this material,and the strain ratcheting occurs obviously at the maximum LCF loading of 900 MPa.The LCF resistance is found to be dependent on both the maximum loading and the stress ratio.The HCF limit stresses for 1 9 107 and 1 9 106 cycles are determined as405.7 and 457.6 MPa,respectively.The macroscopic fatigue fracture mode and the failure features on fracture surfaces were analyzed by scanning electron microscope（SEM）.展开更多
The low cycle fatigue（LCF） tests were carried out using symmetrical cyclic loading under total strain amplitude control conditions.The present paper is devoted to investigating the cyclic deformation response of Ti...The low cycle fatigue（LCF） tests were carried out using symmetrical cyclic loading under total strain amplitude control conditions.The present paper is devoted to investigating the cyclic deformation response of Ti–6Al–4V titanium and the electron-beam-welded（EBW） joint in the following aspects,i.e.,cyclic deformation behavior,fatigue life and fatigue fracture behavior.The results show that the softening of the joint is significant at larger strain ranges,while not obvious at smaller strain ranges.The joint shows shorter fatigue life at larger strain ranges and equivalent fatigue life at smaller strain ranges compared with Ti–6Al–4V base metal.A fatigue crack of the joint not only originates at the surface or subsurface,but also at defects in the fusion zone（FZ）.The crack propagation zone of Ti–6Al–4V base metal shows ductile fracture mechanism,while the joint shows brittle fracture mechanism.In all the fatigue fracture zones many dimples appear,showing the typical ductile fracture.展开更多
基金supported by the National Program on Key Basic Research Project(No.2015CB057400)the National Natural Science Foundation of China(No.NSFC 51275023)the Innovation Foundation of Beihang University for Ph.D.Graduates(No.YWF-14-YJSY-49)
文摘Experimental investigations on the fatigue behavior of a near-alpha titanium alloy under typical cyclic loadings were carried out to simulate the service loading states applied on the engine blades.The axial stress-controlled tension–tension low-cycle fatigue（LCF） tests were carried out over a range of maximum stresses and stress ratios.The rotary bending tests were conducted using a step-loading procedure to reveal the high-cycle fatigue（HCF） limit stresses.The cyclic softening effect is observed in this material,and the strain ratcheting occurs obviously at the maximum LCF loading of 900 MPa.The LCF resistance is found to be dependent on both the maximum loading and the stress ratio.The HCF limit stresses for 1 9 107 and 1 9 106 cycles are determined as405.7 and 457.6 MPa,respectively.The macroscopic fatigue fracture mode and the failure features on fracture surfaces were analyzed by scanning electron microscope（SEM）.
基金financially supported by the HiTech Research and Development Program of China(No.2012AA052102)the Program of International Science Technology Cooperation of China(No.2013DFA61590)
文摘The low cycle fatigue（LCF） tests were carried out using symmetrical cyclic loading under total strain amplitude control conditions.The present paper is devoted to investigating the cyclic deformation response of Ti–6Al–4V titanium and the electron-beam-welded（EBW） joint in the following aspects,i.e.,cyclic deformation behavior,fatigue life and fatigue fracture behavior.The results show that the softening of the joint is significant at larger strain ranges,while not obvious at smaller strain ranges.The joint shows shorter fatigue life at larger strain ranges and equivalent fatigue life at smaller strain ranges compared with Ti–6Al–4V base metal.A fatigue crack of the joint not only originates at the surface or subsurface,but also at defects in the fusion zone（FZ）.The crack propagation zone of Ti–6Al–4V base metal shows ductile fracture mechanism,while the joint shows brittle fracture mechanism.In all the fatigue fracture zones many dimples appear,showing the typical ductile fracture.
